CN101740668A - Light emitting element - Google Patents

Abstract

The invention discloses a light emitting device, comprising a semiconductor stack having an active layer, wherein the active layer is a multi-quantum well (MQW) structure formed by alternately stacking a plurality of quantum well layers and a plurality of barrier layers, and at least one of the barrier layers is a doped barrier layer and an undoped barrier layer. The doped barrier layer can improve the carrier mobility of holes, homogenize the light-emitting region in the active layer and improve the Internal Quantum Efficiency (IQE) of the light-emitting element.

Description

Light emitting element

technical field

The present invention relates to a light-emitting device structure, in particular to a light-emitting device with at least one doped barrier layer and one undoped barrier layer in the active layer.

Background technique

Light-emitting diode (LED) is a widely used light source in optoelectronic components. Compared with traditional incandescent bulbs or fluorescent tubes, light-emitting diodes have the characteristics of energy saving and long service life, so they gradually replace traditional light sources and are used in various fields, such as traffic signs, backlight modules, street lighting, medical equipment wait.

FIG. 1A is a schematic structural view of a known light-emitting element. As shown in FIG. 1A, a known light-emitting element 100 includes a substrate 10, a semiconductor stack 12 on the substrate 10, and an electrode 14 on the semiconductor stack 12, wherein the semiconductor The laminated layer 12 comprises at least a p-type semiconductor layer 120, an active layer 122, and an n-type semiconductor layer 124 from top to bottom; in addition, in the known light-emitting element 100, its active layer 122 is a multiple quantum well (Multiple Quantum Well) Well, MQW) structure, the so-called "multiple quantum well structure" means that the active layer 122 is a region in which multiple quantum well layers (quantum well layers) 126 and multiple barrier layers 128 (barrier layers) are stacked alternately.

The light-emitting principle of the light-emitting diode 100 is that electrons and holes are respectively injected into the active layer 122 by the n-type semiconductor layer 124 and the p-type semiconductor layer 120, and electrons e and holes h recombine in the quantum well layer 126 in the active layer 122. And release energy in the form of light. Figure 1B is a schematic diagram of the energy gap (bandgap) and light-emitting mechanism of a known light-emitting diode. As shown in Figure 1B, since the carrier mobility of the hole h is smaller than that of the electron e, it has been It is known that the electrons e and the holes h in the light emitting diode 100 are often only recombined in the quantum well layer 126 closer to the p-type semiconductor layer 120, so the light-emitting region in the active layer 122 is concentrated near the p-type semiconductor 124. Near the quantum well layer 126, only a few structures in the active layer 122 can emit light.

Contents of the invention

The main purpose of the present invention is to disclose a light-emitting element, including a semiconductor stack, wherein the semiconductor stack has an active layer, and the active layer also includes a plurality of quantum well layers and a plurality of barrier layers stacked adjacently and alternately, wherein the above-mentioned plurality The barrier layer has at least one doped barrier layer and one undoped barrier layer.

Another object of the present invention is to provide a light-emitting device with an active layer of a multi-quantum well structure, wherein the multi-quantum well structure has a selective p-type doped barrier layer to increase the carrier mobility of holes.

Another object of the present invention is to improve the carrier mobility of holes through the barrier layer with selective p-type doping in the multi-quantum well structure, so that the holes are evenly distributed in the active layer, thereby increasing the number of quantum wells. The light-emitting area of the well structure and improve the internal quantum efficiency.

Description of drawings

FIG. 1A is a schematic structural diagram of a known light-emitting element.

FIG. 1B is a schematic diagram of a known light-emitting device energy gap and light-emitting principle.

Fig. 2 is a schematic structural diagram of an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of another embodiment of the present invention.

Fig. 4 is a schematic structural diagram of yet another embodiment of the present invention.

Fig. 5 is a structural diagram of another embodiment of the present invention.

Fig. 6 is a structural diagram of another embodiment of the present invention.

Fig. 7 is a structural diagram of another embodiment of the present invention.

Fig. 8 is a schematic diagram of an energy gap of an embodiment of the present invention.

Explanation of reference signs

100: Light emitting element 10: Substrate

12: Semiconductor stack 120: p-type semiconductor layer

122: Active layer 124: n-type semiconductor layer

126: quantum well layer 128: barrier layer

14: Electrode 200: Light emitting element

20: Substrate 22: Semiconductor stack

220: first conductivity type semiconductor layer 222: active layer

224: Second conductivity type semiconductor layer 226: Quantum well layer

228: Base layer 2280: Outside base layer

2282: inner barrier layer 2282': p-type doped barrier layer

24: electrode

Detailed ways

Embodiments of the present invention are described below with reference to the accompanying drawings.

2 and 3 are structural schematic diagrams of embodiments of the present invention. As shown in FIG. 2, the light-emitting element 200 includes a substrate 20, a semiconductor stack 22 on the substrate 20, and at least one electrode 24 on the semiconductor stack 22, wherein the above-mentioned substrate 20 can be an insulating, conductive, transparent or light-absorbing substrate , its material can be metal, zinc oxide (ZnO), silicon carbide (SiC), sapphire (sapphire), silicon (silicon), gallium arsenide (GaAs) or gallium phosphide (GaP) and other materials, and the above-mentioned semiconductor stack The material of layer 22 may be selected from III/V semiconductor materials including aluminum (Al), gallium (Ga), indium (In), phosphorus (P), arsenic (As) or nitrogen (N), such as nitride Gallium (GaN) series materials, aluminum gallium indium phosphide (AlGaInP) series materials or gallium arsenide (GaAs) materials, etc.; in this embodiment, the substrate 20 is a zinc oxide conductive transparent substrate and the semiconductor stack 22 is a gallium nitride series Materials are explained.

Above-mentioned semiconductor laminated layer 22 comprises at least first conductive type semiconductor layer 220, active layer 222, and second conductive type semiconductor layer 224 from top to bottom, wherein this active layer 222 is made of multiple quantum well layers (quantum well layer ) 226 and a plurality of barrier layers (barrier layer) 228 are adjacent and stacked to form a multiple quantum well (multiple quantum well) structure, wherein the material of the quantum well layer 226 is indium gallium nitride (InGaN), and the barrier layer 228 The material used is gallium nitride (GaN).

The above multiple barrier layers 228 include the outer barrier layer 2280 closest to the first conductive type semiconductor layer 220 and the second conductive type semiconductor layer 224, and the inner barrier layer 2282; among the above inner barrier layers 2282, one is selected arbitrarily One or more inner barrier layers are doped, and the impurity is a p-type dopant, and its material can be beryllium (Be), magnesium (Mg), barium (Ba) or carbon (C). In other words, in the embodiment of the present invention, the inner barrier layer 2282 includes at least a p-type doped barrier layer 2282' having p-type dopants, and the outer barrier layer 2280 is an undoped barrier layer.

As shown in FIG. 2 , in this embodiment, the active layer 222 is an example of a structure in which 10 pairs of (pair) barrier layers 228 and quantum well layers 226 are adjacent and alternately stacked. , the inner barrier layer 2282 located in the middle of the active layer 222 can be selected for doping, in other words, the fifth barrier layer close to the first conductivity type semiconductor layer 220 can be selected for doping to form a p-type doped barrier layer 2282'.

In addition, in the embodiment of the present invention, as shown in FIG. 3 , the barrier layer 228 of the third layer and the seventh layer close to the first conductivity type semiconductor layer 220 can be selected for doping to form a p-type doped barrier layer 2282. ', so that the p-type doped barrier layer 2282' is uniformly distributed in the active layer 222.

The p-type doped barrier layer 2282' of the present invention, in addition to being located in the middle of the active layer 222 or evenly distributed in the active layer 222 as shown in Figure 2 or Figure 3, can also be as shown in Figure 4 and Figure 5 are unevenly distributed in the active layer 222 . 4 and 5 are structural schematic diagrams of another embodiment of the present invention. As shown in FIG. 4 , in the inner barrier layer 2282, a region close to the first conductivity type semiconductor layer 220 is selected for p-type doping, so that the p-type doped barrier The layer 2282 ′ is formed in a region close to the first conductivity type semiconductor layer 220 . In addition, as shown in FIG. 5 , in the inner barrier layer 2282, a region close to the second conductive type semiconductor layer 224 can be selected for p-type doping, so that the p-type doped barrier layer 2282' is formed near the second conductive type semiconductor layer. Layer 224 area.

Furthermore, in the light-emitting element 200 disclosed in the present invention, in addition to uniformly doping and distributing the dopant in the p-type doped barrier layer 2282 ′, the dopant can also be concentrated in the p-type doped barrier layer 2282 'Specific doped regions. Figure 6 and Figure 7 are schematic structural diagrams of another embodiment of the present invention, as shown in Figure 6, the embodiment of the present invention is to dope impurities into the p-type doped barrier layer 2282' by delta doping , so that the p-type doped barrier layer 2282' forms a structure in which the undoped region B sandwiches the doped region A; as shown in Figure 7, the doped region A is located in the p-type doped barrier layer 2282' and is close the quantum well layer region.

Fig. 8 is a schematic diagram of the energy gap of the embodiment of the present invention. As shown in Fig. 8, the p-type doped barrier layer 2282' improves the mobility of the holes h, increases the injection amount of the holes h, and makes the holes h more uniform. are distributed in the active layer 222 , so that the electron e and the hole h recombine (recombine) region is relatively uniform.

Through the light-emitting element structure disclosed in the present invention, the probability of internal quantum recombination of the light-emitting element 200 can be increased to improve internal quantum efficiency and brightness of the light-emitting element.

The above-described embodiments are only to illustrate the technical ideas and characteristics of the present invention, and its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. When it is not possible to limit the claims of the present invention, that is, generally Equivalent changes or modifications made according to the spirit disclosed in the present invention shall still be covered by the claims of the present invention.

Claims (12)

1. light-emitting component, at least comprise first conductive-type semiconductor layer, active layer, and second conductive-type semiconductor layer, wherein this active layer is by a plurality of quantum well layers and a plurality of layer multi-quantum pit structure that is staggeredly stacked and is formed of building, at least comprise the p type in this a plurality of bases layer and mix and build layer, and the base layer of the most close this first conductive-type semiconductor layer or this second conductive-type semiconductor layer is built for not mixing layer.

2. light-emitting component as claimed in claim 1, wherein the alloy of this p type doping base layer is beryllium, magnesium, barium or carbon.

3. light-emitting component as claimed in claim 2, wherein this alloy is distributed in this p type equably and mixes to build in the layer or be distributed in this p type and mix and build specific region in the layer.

4. light-emitting component as claimed in claim 3, wherein the specific region in this p type doping base layer is the part near this quantum well layer.

5. light-emitting component as claimed in claim 2, wherein this alloy is doped in this p type doping base layer with the method for δ doping.

6. light-emitting component as claimed in claim 1, wherein the material of this first conductive-type semiconductor layer, active layer and second conductive-type semiconductor layer is selected from the semiconductor substance that comprises aluminium, gallium, indium, nitrogen, phosphorus or arsenic.

7. light-emitting component, comprise semiconductor laminated, wherein this semiconductor laminatedly has an active layer, this active layer comprises a plurality of quantum well layers and builds the multi-quantum pit structure that layer is staggeredly stacked and is formed, wherein this base layer comprises at least one outside base layer and a plurality of inboard layer of building, wherein this outside is built layer and is built layer for mixing, and comprise a p type at least and mixes and build layer and should the inboard build layer.

8. light-emitting component as claimed in claim 7, wherein the alloy of this p type doping base layer is beryllium, magnesium, barium or carbon.

9. light-emitting component as claimed in claim 8, wherein this alloy is distributed in this p type equably and mixes to build in the layer or be distributed in this p type and mix and build specific region in the layer.

10. light-emitting component as claimed in claim 9, wherein the specific region in this p type doping base layer is the part near this quantum well layer.

11. light-emitting component as claimed in claim 8, wherein this alloy is doped in this p type doping base layer with the method for δ doping.

12. light-emitting component as claimed in claim 7, wherein this semiconductor laminated material is selected from the semiconductor substance that comprises aluminium, gallium, indium, nitrogen, phosphorus or arsenic.

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